The driver behind the wheel of the truck that plowed into a limo bus carrying Tracy Morgan early Saturday morning pleaded not guilty on Wednesday to one count of vehicular homicide and four counts of assault by auto. If convicted, each count of assault by auto carries a maximum 18-month prison term, while the vehicular homicide charge carries a five- to 10-year prison sentence.

Comedian James "Jimmy Mack" McNair, a longtime friend and mentor of Morgan's, was killed and four others were injured. Morgan, 45, underwent surgery for a broken leg on Sunday and remains hospitalized in critical yet stable condition.

In a statement yesterday, his rep said that the 30 Rock star's condition had not changed and they would be withholding further comment until there was new information to report. On Monday his camp denied rumors that one of Morgan's legs had to be amputated.

The criminal complaint alleges that Roper, a driver for Walmart, had supposedly not slept for more than 24 hours before the crash, which occurred on the New Jersey Turnpike after Morgan had performed in Dover, Del.

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Walmart has stated that it believes Roper was abiding by federal driver safety guidelines, which mandate that a driver spend at least 10 hours not behind the wheel before starting a shift, and that no shift last longer than 14 hours, including 11 hours of driving, and was prepared to take full responsibility for the accident if the truck was to blame.

"The details are the subject of the ongoing investigation and we are cooperating fully with the appropriate law enforcement agencies," the retailer stated.

Roper, 35, remains free on $50,000 bail. According to the New Jersey Star-Ledger, Superior Court Judge Bradley Ferencz noted during the arraignment that Roper had a previously clean driving record. Neither the accused nor his attorney spoke with reporters after court.